Energy comes in many forms and is stored in many guises. There are chemical (carbon/oxygen and hydrogen/oxygen), nuclear (fission and fusion), photo-voltaic (solar cells) and mechanical (wind, hydro-electric and geothermal) sources of energy, and people have made use of them all. Most energy sources are used to provide either electrical or mechanical power and for each there is a price to pay. Some conversion processes are more efficient than others, some are more suitable for large scale industrial or regional applications than others but almost all have environmental impacts. This invention, a distributed system of electrical generators utilizing wind driven natural motion of trees (henceforth referred to as e-Trees), represents a new and strikingly novel technology for producing electrical power in conditions where conventional (both renewable and non-renewable) alternatives are too expensive or problematic to be commercially or environmentally viable.
e-Trees makes use of the natural and persistent mechanical motion of trees to produce electricity. Once one understands the potential of this approach it is forevermore impossible to look at gently swaying trees on wooded land without imagining its potential to produce power from that motion. The principle is simple. Trees, when subjected to wind will naturally sway back and forth. Like a spring subjected to a driving force trees will undergo periodic motions (they will sway) as they are subjected to the winds' forces. As no two trees are identical, no two trees will sway in exactly the same way, i.e., with the same frequency and phase even when subjected to the same driving force. Trees are also massive, carbon-rich organisms and so serve as very effective sequesters of carbon. Trees' motions are essentially unstoppable and regular (essentially periodic) and therefore deriving power from them is possible even when the motion is very slight (just a few inches is sufficient—small, powerful motions can be “ratcheted up” to yield the necessary torque to drive conventional generators). e-Trees harness the immutable, essentially independent periodic motion of trees to produce electricity. By interconnecting neighboring trees on a wooded plot of land, suspending between the trees small pull-retract generators (PRGs) one can convert the constant, independent small swaying motions of the trees, regardless of the wind direction, into electricity. Each PRG is connected, through a rectifier for DC generators to insure no current flows backwards into the PRG, to local controllers (conditioners and inverters) so as to regulate their output and to convert it into AC or DC (as needed) of the proper voltage so that it can be integrated with other systems.
e-Tree farms (many “harnessed” trees) produce electricity naturally. They have very minimal impact on the environment, both esthetically and ecologically. And, they can be located at almost any windy place where there are tall trees (or where one can plant trees)—from residential neighborhoods to remote mountain ridges. A significant cost and drawback to conventional wind turbine technology is the need to find cleared land, away from bird and bat habitats and not too close to people. The problematic effects of modern industry on the atmospheric levels of greenhouse gases like carbon dioxide are profound, and the clearing of trees and the destruction of otherwise natural ecosystems required for the installation of conventional turbine projects contributes to those problems even as the wind turbine technology produces clean energy. e-Tree farms on the other hand promote the planting of trees, and as each tree acts like a giant wick soaking up atmospheric carbon this approach to generating electricity is doubly beneficial. This object of this patent application provides power and at the same time benefits the environment. e-Trees installations promote the planting of trees (and hence, carbon sequestration) and produce electricity. Some trimming and thinning of wooded properties often needs to be done to achieve the most efficient e-Tree installation, but this is often beneficial to the trees and to the forest ecosystem.
Theoretically, e-Tree farm output is proportional to the area of e-Tree farm (related to the number of PRGs), and like wind turbine technology is an increasing function of the wind speed, turbulent or uni-directional. Conventional turbines require slowly varying or uni-directional persistent winds and they are manufactured with the limited ability to rotate their position as the wind speed and direction changes. In contrast, e-Trees function in either persistent or turbulent winds. In fact, turbulent wind patterns will typically produce more relative tree motion and hence produce more electrical yield. As an e-Tree installation ages or as wind patterns change (a likely scenario if global warming continues to progress), the PRGs can be removed or re-positioned to take advantage of the changes. Conventional turbine installations do not support that sort of adaptation. e-Trees typically complement, rather than compete with, conventional wind turbine technologies.
The optimal design of an e-Tree installation is a complex process. For instance, the mathematical models estimating yield can not incorporate all of the natural detail of a stand of trees, manufactured by nature and not a man-made process with uniform specifications and control, which naturally includes different species of trees and trees of varying ages. The optimal placement of the PRGs (e.g., at what height they should be hung and between which trees they should be suspended) on land supporting different species of trees and for different wind profiles must be determined empirically. Because e-Tree farms can cover large parcels of land, e-Tree farms must often manage the transmission line attenuation problem. Large e-tree farms can extend over many acres and that means that the power lines that carry the electricity to the user (e.g., the regional or local electrical grid) will necessarily be long. Power lines loose power (owing to the resistance present in the power line) and it is certainly possible for there to be significant loss to an e-Tree farm's yield by the time it is connected to the user if that user is too far away. e-Tree projects can be installed closer to the user in many cases and thereby mitigate the transmission line problem. For truly remote installations of large (MW output) e-Trees projects, there must be sufficiently developed transmission line infrastructure. This is of course a problem for traditional wind turbines as they are often required (for aesthetic, zoning and safety reasons) to be far removed from their customers.
Careful planning is necessary if an e-Tree farm is to be cost effective. But in many cases, these installations can be the only reasonable way to locally generate electrical power (e.g., one or two PRG installations that provide power to charge suburbanites' plug-in hybrid automobiles). In many cases net metering regulations allow the owner of an e-Tree installation to be paid for electricity supplied to the local electrical grid. The scale of an e-Tree installation can vary between those utilizing only a few trees (generating a few hundred watts) and those utilizing many thousands of trees (generating hundreds of KWs or even MWs). This new technology requires very little infrastructure, the process of installing an e-Tree farm makes use of little machinery and has little impact on the trees and on the local ecology. Maintenance is handled by e-Tree “forest rangers.” These rangers can be members of the indigenous population who shepherd the e-Tree farms by tending to the health of the trees (trimming, thinning and readjusting the PRG harnesses) and maintaining the equipment.
e-Tree technology, a distributed system of electrical generators utilizing wind driven natural motion of trees, represents a technology that can be used around the world by individuals and governments interested in producing electricity with minimal environmental impact while mitigating the effects of atmospheric carbon dioxide and contributing to the fight against global warming.